JJ ans
onion 2003-08-29 10:21:01
(2) 数列a1,a2,a3……，a3=a2+a1,a4=a1+a2+a3,依此类推， an=p,问a(n+2)=？
答案 4p
求过程?

an=p
=a(n-1)+a(n-2)+......+3+2+1
a(n+1)=a(n)+a(n-1)+a(n-2)+......+3+2+1
~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~
=P + P
=2P
therefore,
a(n+2)= a(n+1)+an+a(n-1)+a(n-2)+......+3+2+1
= 2P + p+ p
=4P

　

Copyright 1999-2006 Microedu.com: GMAT GRE and LSAT Prep. Not affiliated with Microsoft. 

微迪留学网中文版版权所有，转载请注明出处